Neck Injury Criterion (Nij)

Overview:

Neck Injury Criterion (Nij) uses the neck axial force and the neck flexion/extension moment of the upper or lower neck to predict injury. A Nij value greater than one correlates to 50% injury risk ?

Required Signals:

• Flexion/Extension Moment of the Upper or Lower Neck (Y)
• Tension/Compression Force of the Upper or Lower Neck (Z)

Calculation:

1. Filter neck force data (CFC = 1000) and neck moment data (CFC = 600) according to J211-1
2. Apply Neck Moment Corrections
3. Calculate Nij for each polarity permutation

$$\tag{Equation 1}N_{ij} = \frac{F_z}{F_{zc}} + \frac{M_y}{M_{yc}}$$

$F_z$ = Axial Force, $F_{zc}$ = Critical Force Value, $M_y$ = Flexion/Extension Moment, $M_{yc}$ = Critical Moment Value

---

Polarity Permuations

$N_{ij}$	Force Condition	Moment Condition
Ntf	$F_z>0$, Tension	$M_y>0$, Flexion
Nte	$F_z>0$, Tension	$M_y<0$, Extension
Ncf	$F_z<0$, Compression	$M_y>0$, Flexion
Nce	$F_z<0$, Compression	$M_y<0$, Extension

---

Reference Values

Upper Neck Critical Values In-Position

ATD	$F_{zc} (N)$ ($F_{zc}>0$, Tension)	$F_{zc} (N)$ ($F_{zc}<0$, Compression)	$M_{yc} (Nm)$ ($M_{oc,y}>0$, Flexion)	$M_{yc} (Nm)$ ($M_{oc,y}<0$, Extension)
HIII - M95	8180	-7480	405	-177
HIII - M50	6806.0	-6160.0	310.0	-135.0
HIII - F05	4287	-3880	155	-67
HIII - 10yo	3710	-3390	125	-54.8
HIII - 6yo	3080	-2820	96	-42
HIII - 3yo	2330	-2130	67	-29.3
CRABI - 18mo	1760	-1610	46.8	-20.4
CRABI - 12mo	1610	-1470	42.5	-18.6
CRABI - 6mo	1510	-1380	39.5	-17.3

Upper Neck Critical Values Out-of-Position

ATD	$F_{zc} (N)$ ($F_{zc}>0$, Tension)	$F_{zc} (N)$ ($F_{zc}<0$, Compression)	$M_{yc} (Nm)$ ($M_{oc,y}>0$, Flexion)	$M_{yc} (Nm)$ ($M_{oc,y}<0$, Extension)
HIII - M95	7480	-7480	405	-162
HIII - M50	6200.0	-6200.0	305.0	-122.0
HIII - F05	3880	-3880	155	-61
HIII - 10yo	3390	-3390	125	-50.1
HIII - 6yo	2800	-2800	93	-37
HIII - 3yo	2120	-2120	68	-27
CRABI - 18mo	1610	-1610	46.8	-18.7
CRABI - 12mo	1460	-1460	43	-17
CRABI - 6mo	1380	-1380	39.5	-15.8

Lower Neck Critical Values In-Position

ATD	$F_{zc} (N)$ ($F_{zc}>0$, Tension)	$F_{zc} (N)$ ($F_{zc}<0$, Compression)	$M_{yc} (Nm)$ ($M_{oc,y}>0$, Flexion)	$M_{yc} (Nm)$ ($M_{oc,y}<0$, Extension)
HIII - M95	8180	-7480	405	-177
HIII - M50	6780.0	-6200.0	610.0	-266.0
HIII - F05	4287	-3880	155	-67
HIII - 10yo	3710	-3390	125	-54.8
HIII - 6yo	3080	-2820	96	-42
HIII - 3yo	2330	-2130	67	-29.3
CRABI - 18mo	1760	-1610	93.6	-40.8
CRABI - 12mo	1610	-1470	85	-37.2
CRABI - 6mo	1510	-1380	79	-34.6

Lower Neck Critical Values Out-of-Position

ATD	$F_{zc} (N)$ ($F_{zc}>0$, Tension)	$F_{zc} (N)$ ($F_{zc}<0$, Compression)	$M_{yc} (Nm)$ ($M_{oc,y}>0$, Flexion)	$M_{yc} (Nm)$ ($M_{oc,y}<0$, Extension)
HIII - M95	7480	-7480	405	-162
HIII - M50	6200.0	-6200.0	610.0	-244.0
HIII - F05	3880	-3880	155	-61
HIII - 10yo	3390	-3390	250	-50.1
HIII - 6yo	2820	-2820	192	-76.8
HIII - 3yo	2120	-2120	68	-27
CRABI - 18mo	1610	-1610	93.6	-37.4
CRABI - 12mo	1470	-1470	85	-34
CRABI - 6mo	1380	-1380	79	-31.6

Injury Criteria

Parameter	IARV	Good - Acceptable	Acceptable - Marginal	Marginal - Poor
$N_{ij}$	1.00	0.80	1.00	1.20
Neck Axial Tension (kN)	3.3	2.6	3.3	4.0
Neck Compression (kN)	4.0	3.2	4.0	4.8